Traffic cones are used for a variety of traffic control purposes, for example to warn drivers of the presence of roadworks, and to direct the flow of traffic along preferred lines. To carry out their functions properly, the cones must be clearly visible even at night and under adverse weather conditions, and to this end they are frequently provided with one or more light reflecting surfaces, which reflect light from the headlamps of oncoming vehicles. When reflection of light is insufficient, it is common to position a warning light on the traffic cone, the warning light comprising a battery housing and a head projecting upwardly therefrom. The head contains a lamp powered by a battery in the battery housing and a lens for controlling the direction in which light from the lamp is transmitted as a substantially unidirectional beam in a single or in two opposite, parallel directions.
It is evident, considering the profusion of traffic cones on motorways, that only the simplest systems for mounting the housing on the traffic cone are practicable. In one such known mounting system, the battery housing is mounted on a circular bracket which may be positioned as a collar around the conical neck of a traffic cone. Thus, in use with the collar located on the neck of the traffic cone, the battery housing and head of the warning light are presented at one side of the cone.
This known mounting system has been employed on roads worldwide, but it suffers from a number of disadvantages. One is its mechanical instability: the weight of the warning light, when fitted with a battery, is normally comparable with that of the traffic cone on the side of which the warning light is supported. Thus, the warning light tends to destabilize the traffic cone. Furthermore, the exposed head of the warning light is liable to be caught by high winds. The possible consequences of the cone or warning light being knocked over are all too obvious: the warning light may be damaged as it hits the ground; the disappearance of the traffic light will result in hazardous areas being insufficiently marked out; and above all, the cone and warning light may fall into the path of traffic, thus creating a new, highly significant traffic hazard.
Roadworkers who fit warning lights onto traffic cones have noticed the instability of this known mounting system, and as a result frequently attempt to make the head of the warning light less exposed by fitting the warning light upside down on the traffic cone, that is with the head projecting downwardly beneath the battery housing. This makes the warning light less visible and misdirects the beam from the optimum direction for maximum effectiveness. Furthermore, many designs of warning light are such that when positioned upside down in this way, they have a disadvantageous tendency to collect rainwater within the head.
Another feature of the known warning light described above is that the battery is generally retained inside the battery housing by a mechanism in which screwthreaded elements are used either to connect the battery directly to the housing, or to hold together elements which enclose the battery. These screw-threaded elements must be laboriously removed and repositioned whenever a battery is renewed. So as to prevent theft of the battery, the screw-threaded elements are usually locked in position such that a key is needed to remove them. This is despite the fact that in many environments, for example motorways, the theft of batteries from warning lights would be uncommon even if their battery housings were not locked.
GB-A-2039354, GB-A-2144532 and GB-A-2199400 discloses various alternative constructions and arrangements of hazard warning lights for mounting on traffic cones. In all of these proposals, the lamp unit is mounted generally vertically above the apex of the cone. However, such arrangements share similar instability problems to the commercially known example discussed above, particularly as regards their top-heaviness.
A further alternative construction of warning light for mounting on a traffic cone is disclosed in GB-A-1503874. In this arrangement the lamp head is still mounted vertically above the apex of the cone, but dual battery compartments are arranged laterally on either side thereof. Whilst this improves the top-heaviness of the combined arrangement somewhat, it still does not optimise the physical stability of the cone-mounted unit, especially against high winds, and furthermore the disclosed construction is applicable only to dual battery-powered lamps, which frequently may not be desirable or practical.